1、Designation: A910/A910M 18Standard Specification forUncoated, Weldless, 2-Wire and 3-Wire Steel Strand forPrestressed Concrete1This standard is issued under the fixed designation A910/A910M; the number immediately following the designation indicates the yearof original adoption or, in the case of re
2、vision, the year of last revision. A number in parentheses indicates the year of last reapproval.A superscript epsilon () indicates an editorial change since the last revision or reapproval.1. Scope*1.1 This specification covers two types and two grades of2-wire and 3-wire, uncoated steel strand for
3、 use in prestressedconcrete construction. The two types of strand are low-relaxation and stress-relieved (normal-relaxation). Low-relaxation is to be regarded as the standard type. Stress-relieved (normal-relaxation) strand will not be furnished unlessspecifically ordered. The two grades are 250 172
4、5 and 2701860. Grades 250 1725 and 270 1860 have minimumtensile strengths of 250 ksi 1725 MPa and 270 ksi 1860MPa respectively, based on the nominal area of the strand.1.2 This specification is applicable for orders in eitherinch-pound units (as Specification A910) or in SI units (asSpecification A9
5、10M).1.3 The values stated in either inch-pound units or SI unitsare to be regarded separately as standard. Within the text, theSI units are shown in brackets. The values stated in eachsystem are not exact equivalents; therefore, each system shallbe used independently of the other. Combining values
6、from thetwo systems may result in non-conformance with the specifi-cation.1.4 This international standard was developed in accor-dance with internationally recognized principles on standard-ization established in the Decision on Principles for theDevelopment of International Standards, Guides and Re
7、com-mendations issued by the World Trade Organization TechnicalBarriers to Trade (TBT) Committee.2. Referenced Documents2.1 ASTM Standard:2A1061/A1061M Test Methods for Testing Multi-Wire SteelPrestressing Strand2.2 U.S. Military Standard:3MIL-STD-129 Marking for Shipment and Storage2.3 Federal Stan
8、dard:3Fed. Std. No. 123 Marking for Shipments (Civil Agencies)3. Terminology3.1 Definition of Term Specific to This Specification:3.1.1 strand, neither two or three wires helically woundaround each other with uniform pitch not less than 12 and notmore than 16 times the nominal diameter of the strand
9、.3.1.1.1 DiscussionThe direction of lay is either right-handed or left-handed.4. Ordering Information4.1 Orders for 2-wire or 3-wire weldless steel strand underthis specification shall contain the following information:4.1.1 Quantity (feet metres),4.1.2 Nominal diameter and description of strand (Ta
10、ble 1),4.1.3 Number of wires (2 or 3),4.1.4 Grade of strand,4.1.5 Type of strand (low-relaxation or stress-relieved (nor-mal relaxation), and4.1.6 ASTM designation A910 A910M and year of issue.4.2 The purchaser shall have the option to specify additionalrequirements, including but not limited to, th
11、e following:4.2.1 Relaxation evidence from similarly dimensionedstrand of the same grade (6.5.1),4.2.2 Specially-dimensioned strand (7.3),4.2.3 Requirements for inspection (11.1),4.2.4 Load-elongation curve (13.2),4.2.5 Packaging and package marking (Section 14), and4.2.6 Other special requirements,
12、 if any.5. Materials and Manufacture5.1 Base MetalThe base metal shall be carbon steel ofsuch quality that when drawn to wire, fabricated into strandand then thermally treated, it shall have the properties andcharacteristics prescribed in this specification.1This specification is under the jurisdict
13、ion of ASTM Committee A01 on Steel,Stainless Steel and Related Alloys and is the direct responsibility of SubcommitteeA01.05 on Steel Reinforcement.Current edition approved March 1, 2018. Published March 2018. Originallyapproved in 1992. Last previous edition approved in 2016 as A910/A910M 16.DOI: 1
14、0.1520/A0910_A0910M-18.2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at serviceastm.org. For Annual Book of ASTMStandards volume information, refer to the standards Document Summary page onthe ASTM website.3Available from U.S. Government Printi
15、ng Office, Superintendent ofDocuments, 732 N. Capitol St., NW, Washington, DC 20401-0001, http:/www.access.gpo.gov.*A Summary of Changes section appears at the end of this standardCopyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United StatesThis in
16、ternational standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for theDevelopment of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT)
17、Committee.15.2 WireThe wire from which the strand is to be fabricatedshall be round and have a dry-drawn finish.NOTE 1This product is a composite of two or three wires and isproduced only to meet the prescribed mechanical properties, of which thechemical composition of all wires or any individual wi
18、re is not pertinentto this application, and heat identity is not necessarily maintained. It ispossible that wire from more than one heat may be used in themanufacture of a reel or reelless pack. Traceability is based on the identityof reels or reelless packs as maintained and reported by the manufac
19、turer.5.3 TreatmentAfter stranding, low-relaxation strand shallbe subjected to a continuous thermo-mechanical treatment toproduce the prescribed mechanical properties. For stress-relieved (normal-relaxation) strand, only thermal treatment isnecessary. Temper colors that result from the stress-reliev
20、ingoperation are considered normal for the finished appearance ofthis strand.6. Mechanical Property Requirements6.1 Tests for mechanical properties shall be conducted inaccordance with Test Methods A1061/A1061M. Low-relaxation strand shall also be tested as prescribed in TestMethods A1061/A1061M.6.2
21、 Breaking StrengthThe breaking strength of the fin-ished strand shall conform to the requirements prescribed inTable 1.6.3 Yield StrengthYield strength in lbs kN shall bemeasured at 1 % extension under load in accordance with thetest procedure delineated in Test Methods A1061/A1061M,Section 9.1. The
22、 minimum yield strength shall be 90 % forlow-relaxation strand and 85 % for stress-relieved (normal-relaxation) strand of the breaking strength listed in Table 1.Initial loads for the test and minimum yield strengths are listedin Table 2.6.3.1 The extension under load shall be measured by anextensom
23、eter calibrated with the smallest division not largerthan 0.0001 in./in. 0.0001 mm/mm of gage length.6.4 ElongationThe total elongation under load shall bedetermined in accordance with Test Methods A1061/A1061M,Section 9.2. The total elongation under load shall not be lessTABLE 1 Breaking Strength R
24、equirementsDescription and Nominal Diameter of StrandBreaking Strength ofStrandSteel Area ofStrandWeight Mass ofStrandin. mmDescriptionNominalDiameterDescriptionNominalDiameterlbf kN in.2mm2 lbs/1000 ft kg/1000 mGRADE 250 1725 MPa2 0.114 0.228 2 2.90 5.8 5000 22.2 0.020 13.2 69.9 104.03 0.089 0.189
25、3 2.25 4.8 4750 21.1 0.019 12.0 63.3 94.23 0.095 0.205 3 2.40 5.2 5250 23.4 0.021 13.6 71.9 107.03 0.114 0.244 3 2.90 6.2 7750 34.5 0.031 19.8 104.0 155.03 0.118 0.256 3 3.00 6.5 8250 36.7 0.033 21.3 112.0 167.03 0.138 0.295 3 3.50 7.5 11 250 50.0 0.045 29.0 153.0 228.03 0.158 0.340 3 4.00 8.6 14 50
26、0 64.5 0.058 37.4 200.6 298.4GRADE 270 1860 MPa2 0.114 0.228 2 2.90 5.8 5400 24.0 0.020 13.2 69.9 104.03 0.089 0.189 3 2.25 4.8 5130 22.8 0.019 12.0 63.3 94.23 0.095 0.205 3 2.40 5.2 5670 25.2 0.021 13.6 71.9 107.03 0.114 0.244 3 2.90 6.2 8370 37.2 0.031 19.8 104.0 155.03 0.118 0.256 3 3.00 6.5 8910
27、 39.6 0.033 21.3 112.0 167.03 0.138 0.295 3 3.50 7.5 12 150 54.0 0.045 29.0 153.0 228.03 0.158 0.340 3 4.00 8.6 15 660 69.7 0.058 37.4 200.6 298.4TABLE 2 Yield Strength RequirementsDescription and Nominal Diameter of StrandInitial LoadMinimum Load at 1 % Extensionin. mmStress-Relieved(Normal-Relaxat
28、ion)Low-RelaxationDescriptionNominalDiameterDescriptionNominalDiameterlbf kN lbf kN lbf kNGRADE 250 1725 MPa2 0.114 0.228 2 2.90 5.8 500 2.2 4250 18.9 4500 20.03 0.089 0.189 3 2.25 4.8 475 2.1 4038 18.0 4275 19.03 0.095 0.205 3 2.40 5.2 525 2.3 4463 20.0 4725 21.03 0.114 0.244 3 2.90 6.2 775 3.5 658
29、8 29.3 6975 31.03 0.118 0.256 3 3.00 6.5 825 3.7 7013 32.2 7425 33.03 0.138 0.295 3 3.50 7.5 1250 5.0 9563 42.5 10 125 45.03 0.158 0.340 3 4.00 8.5 1450 6.5 12 325 54.8 13 050 11.7GRADE 270 1860 MPa2 0.114 0.228 2 2.90 5.8 540 2.4 4590 20.4 4860 21.63 0.089 0.189 3 2.25 4.8 513 2.3 4360 19.4 4617 20
30、.53 0.095 0.205 3 2.40 5.2 567 2.5 4820 21.4 5103 22.73 0.114 0.244 3 2.90 6.2 837 3.7 7115 31.6 7533 33.53 0.118 0.256 3 3.00 6.5 891 4.0 7574 33.7 8019 36.03 0.138 0.295 3 3.50 7.5 125 5.4 10 328 45.9 10 125 45.03 0.158 0.340 3 4.00 8.6 566 7.0 13 311 59.2 14 094 62.7A910/A910M 182than 3.5 % using
31、 a gage length of not less than 24 in. 600mm. It shall be permissible to determine the total elongationvalue by adding to the 1.0 % yield extension the percentextension or movement between the jaws gripping the strandafter yield determination. The percent is calculated on the newbase length of jaw-t
32、o-jaw distance.6.5 Relaxation PropertiesLow-relaxation strand shallhave relaxation losses of not more than 2.5 % when initiallyloaded to 70 % of specified minimum breaking strength or notmore than 3.5 % when loaded to 80 % of specified minimumbreaking strength of the strand after 1000 h tested in ac
33、cor-dance with the specific procedures in Test Methods A1061/A1061M, Section 9.4.6.5.1 If required, relaxation evidence shall be provided fromthe manufacturers records of tests on similarly dimensionedstrand of the same grade.7. Dimensions and Permissible Variations7.1 The size of the finished stran
34、d shall be expressed as thenominal diameter of the strand in in. mm.7.2 Variations in individual wire diameters shall not because for rejection provided that the other requirements of thisspecification are met.7.3 Specially-Dimensioned Strand:7.3.1 It shall be permitted to furnish, under thisspecifi
35、cation, strands with nominal diameters that are differentthan those listed in Table 1 and Table 2. The breaking strengthshall be defined, and the yield strength, as defined in 6.3, shallnot be less than 90 % and 85 % of the specified minimumbreaking strength for low-relaxation and stress-relieved(no
36、rmal-relaxation) strand, respectively.All other requirementsshall apply.7.4 Permissible Variations in Diameter:7.4.1 All Grade 250 1725 strand shall conform to a sizetolerance of 60.016 in. 60.41 mm from the diametermeasured across the crowns of the wires (2-wire strand only).For 3-wire strand, the
37、diameter is that diameter of a circlewhich can be tangentially circumscribed around the 3 wires.This can be confirmed by comparing the individual wirediameters in the strand to those listed in Table 1 and Table 2.7.4.2 All Grade 270 1860 strand shall conform to a sizetolerance of +0.026 in., 0.006 i
38、n. +0.66 mm, 0.15 mmfrom the nominal diameter measured across the crowns of thewires (2-wire strand only). For 3-wire strand, the nominaldiameter is that diameter of a circle which can be tangentiallycircumscribed around the 3 wires. This can be confirmed bycomparing the individual wire diameters in
39、 the strand to thoselisted in Table 1 and Table 2.8. Workmanship, Finish, and Appearance8.1 Joints:8.1.1 There shall be no strand splices in any length of thecompleted strand.8.1.2 There shall be no wire welds made in the finishedstrands. During manufacturing of individual wires forstranding, weldin
40、g is permitted only prior to or at the size ofthe last thermal treatment (for example, patenting or controlcooling). There shall be no welds in the wire after it has beendrawn through the first die in wire drawing.8.2 When the strand is cut without seizings, the wire shallnot fly out of position. If
41、 any wire flies out of position and canbe replaced by hand, the strand will be considered satisfactory.8.3 The strand shall not be oiled or greased. Slight rusting,provided it is not sufficient to cause pits visible to a person withnormal or corrected vision, shall not be cause for rejection.9. Samp
42、ling9.1 Test specimens cut from either end of the reel or reellesspack are permitted.10. Number of Tests10.1 One test specimen shall be taken from each 30-ton27-tonne production lot of finished strand, and tested forbreaking strength, yield strength, and elongation.11. Inspection11.1 Inspection of t
43、he 2-wire or 3-wire steel strand shall beagreed upon between the purchaser and the manufacturer aspart of the purchase order or contract.12. Rejection and Retesting12.1 Failure of any test specimen to comply with therequirements of the specification shall constitute grounds forrejection of the lot r
44、epresented by the specimen.12.2 The lot shall be resubmitted for inspection by testing aspecimen from each reel or reelless pack and sorting outnon-conforming material.12.3 In case there is a reasonable doubt in the initial testingas to the ability of the strand to meet any requirement of thisspecif
45、ication, two additional tests shall be made on a specimenof strand from the same reel or reelless pack, and if failureoccurs in either of these tests, the strand shall be rejected.13. Certification13.1 At the time of shipment, the purchaser shall befurnished with a written certification that specime
46、ns represent-ing each lot of strand have been tested and conform to therequirements of this specification and that the requirements setforth in the purchase order for inspection, if applicable, havealso been satisfied. The certification shall include ASTMdesignation A910 A910M, year-date of issue, a
47、nd revisionletter, if any.13.2 The manufacturer shall, when requested in the pur-chase order or contract, furnish a representative load-elongation curve for each size and grade of strand shipped.13.3 When the modulus of elasticity of a 2-wire or 3-wirestrand is provided, the cross-sectional area use
48、d to calculate themodulus shall also be provided. The area provided in thecertification shall be the area used to calculate the modulus ofelasticity.13.4 A material test report, certification or inspection, orsimilar document printed from or used in electronic form froman electronic data interchange (EDI) transmission shall beA910/A910M 183regarded as having the same validity as a counterpart printed inthe certifie
